An Introduction to Static Control

Control of static electricity will be required for a number of reasons, but primarily:

• Protection of microelectronic components during assembly, test or repair
• Protection of in electronic equipment in use, e.g., main frame computers
• Prevention of spark generation where flammable gases are used, e.g., hospital operating theatres or areas where explosive are handled or stored
• Prevention of charged surfaces to prevent attraction of particles (clean rooms)
• Personal comfort (protection from electrostatic shock)

When choosing a flooring system designed to control static electricity, one must keep in mind that the base components in the contract are of a more specialised nature than normal. The cost of installing static control flooring is usually more expensive than traditional floorings as the use of specific adhesives and earthing systems is required. The flooring system is usually selected by its static control performance rather than by cost. The cost to clarify at the specification stage is small, the costs to rectify errors post-installation are much higher. The in-use performance specification must be agreed with the end user at the tendering stage and should include method of installation, in-use performance requirements with method of test and maintenance procedures to be used.

There are two main groups into which static control floorcoverings can be divided:

1. STATIC DISSIPATIVE (SD) – compliant products will have resistance to earth between 1 x 107 and 1 x 109Ω
2. ELECTROSTATIC CONDUCTIVE (EC) – compliant products will have resistance to earth of less than 1 x 106Ω

Care must be taken with the lower reading. Most products have a lower limit of 5 x 104Ω as this is generally accepted as providing some protection against mains voltages.

Specialist conductive products are available which have resistance below 5 x 104Ω. Specification of such products is mainly into areas where explosive materials are handled and it is imperative that you liaise with the floor covering manufacturer to ensure the product and installation method used fully meets the design criteria.

Further information on static control is available in the CFA Guide to Contract Flooring.